1. Field of the Invention
The present invention relates to moisture-curable compositions that upon curing provide cured compositions having enhanced elongation and tear properties. These compositions are useful as coatings, adhesives, sealants and composites.
2. Description of Related Art
Moisture-curable silylated resins are useful as coatings, adhesives, sealants and industrial elastomeric goods. Illustratively, U.S. Pat. No. 3,627,722 describes a sealant made from an isocyanate-terminated polyurethane prepolymer wherein at least five percent of the isocyanate groups are end-blocked with trialkoxysilyl groups. U.S. Pat. No. 5,990,257 describes silylated polyurethane prepolymers derived from polyether polyols possessing very low olefinic unsaturation. The cured silylated polyurethane exhibit improved mechanical properties as low-tack sealants. U.S. Pat. No. 6,498,210 describes silylated polyurethane prepolymer containing unreacted isocyanate groups or low molecular weight terminators. Upon curing, the silylated polymers provide improved tensile strength. U.S. Pat. No. 6,001,946 describes a class of moisture-curable N-silylalkyl-aspartic acid ester-terminated polyurethane prepolymers and cured sealant compositions made therefrom that are said to exhibit improved elongation, tensile strength and tear resistance. U.S. Pat. No. 7,319,128 describes organyloxysilyl-terminated polymers obtained by reacting hydroxyl-terminated organic polymers with isocyanato-functional silanes in the presence of a catalyst.
However, conventional coatings, adhesives and sealants based upon these silylated resins do not always provide a desired combination of the aforementioned physical properties. For example, for windshield adhesives, physical properties such as high elongation and tear strength are desired while other desirable mechanical properties are maintained.
Accordingly, there is a continuing need for moisture-curable compositions having enhanced elongation and tear properties.